Twelve years ago this month, I was handed a sensitive document and charged with making sure it found its way into the right hands.

Earlier that year, two friends of mine — girls, who had previously identified as at least mostly straight — had begun dating. It was a brief affair, and seemed to end definitively when one of them, a year older, graduated and went off to college three states away. The other, to whom I was a good bit closer, was hurt. And when Thanksgiving break rolled around and the previous year's seniors came flooding home to visit, she decided to try winning her old flame back — with a mixtape. Why she needed me to play courier was never explained, but I understand now. I'd have felt vulnerable, too.

Both girls were stylish types with eclectic tastes. They were active in school theater and changed their hair color routinely. They smoked and cussed. I'd read sexy poems they'd written in the literary magazine, and heard them speak in reverent tones about bands I'd never heard of. So when one handed me a mysterious totem to give to the other, I was driven mad with curiosity. Home CD burning was still a few years away from ubiquity; this was an actual 90-minute cassette with a handwritten insert, a gift from one teenage aesthete to another. It felt hot in my hands. And so, during the few days the tape was in my custody, I decided to make my own copy.

Whatever coded messages about love and nostalgia lay hidden in the track list were lost on me. Everything I heard was new territory, and it was spellbinding. I enjoyed my first encounters with Elliott Smith and PJ Harvey, a lo-fi gem by the acoustic shredder Mary Lou Lord, curveballs like the Canadian pop-punk outfit Treble Charger and hard evidence that Blur had music beyond "Song 2." In retrospect, 2000 was probably the last year I listened to commercial radio or watched MTV with any regularity. It was the year I turned 16, the year my household finally got an Internet connection and, due in part to those milestones, the year I developed something resembling taste and began to seek out culture rather than waiting for it to come to me. The tape was a treasure in that sense, shining a light on wonders unknown. But lurking among them was something for which I was not prepared. Something menacing.

It would be years before I came into any understanding of the 1990s riot grrrl movement, or of the bracing collision of dance and punk sounds that would become electroclash. But I suspect that even with context on my side, hearing Le Tigre for the first time would have rattled me. "The The Empty" was unlike anything I'd heard before. Every instrument sounded as if it was being played through an old dial-up modem. The vocals were a mix of unintelligible mumbles and raw-throated screams. Singer Kathleen Hanna had a voice battle-tested from her days leading the fiery punk act Bikini Kill, and when she shouted, "Oh, baby," it was without a shred of tenderness. In a basket of candy hearts, this was the one on which you might chip a tooth.

My two friends never did get back together. And as revelatory as it was hearing Le Tigre by accident, I didn't fall in love, either: It was too abrasive, too aggressive for ears only just weaned off the Top 40. In the years that followed, the band's music would cross my path sporadically, in snippets — a late-night TV appearance here, a dance floor jolted to life by "Deceptacon" there. In 2003, the manager at my summer movie-theater job introduced me to his friend Johanna. That this was Johanna Fateman, Le Tigre member and co-founder, escaped me as I nodded hello and went back to wiping down the ticket counter.

So I couldn't tell you why, when the song "Hot Topic" caught my ear at a party earlier this month, something in me wouldn't let it go. The song followed me home; I hummed it in the shower that night, and drifted to sleep with it still in my head. Granted, I'm not the listener today that I was at 16. I've warmed since then to music with strident sounds and singers with unusual voices. I've become a fan of Sleater-Kinney and LCD Soundsystem, who respectively influenced and were influenced by what Hanna and crew were doing at the turn of the millennium. Whatever the reason, I suddenly felt ready to learn. The next morning, before I'd brushed my teeth or eaten breakfast, I logged on to iTunes and bought the band's 1999 debut, Le Tigre.

In two weeks of nonstop listening, one thing has become clear: I would have loved this album in high school if I'd given it a chance. It's frequently hilarious: "What's Yr Take On Cassavetes?" shows a complex debate about hero worship devolve into a silly shouting match ("Misogynist!" "Genius!"). It wears its geography on its sleeve; the New York references in "My My Metrocard" would have hit this East Village kid in the chest. It prefigures the dance revival that would sweep indie rock a few years later: "Hot Topic" serves the same function for feminist scholars that "Losing My Edge" does for urban cool hunters, if much more reverently. And, to my complete surprise, Le Tigre can be gentle. "Eau D' Bedroom Dancing" is a bona fide ballad, the kind of thing you would expect to find on a mixtape passed between lovers.

But then, maybe I missed the point there, as well. I was home for Thanksgiving last week, and after some digging through dusty boxes in my childhood bedroom, I found the dubbed cassette still intact — nestled, fittingly, between mixtapes I'd saved from my own past relationships. As I listened on my mother's vintage Walkman, I was struck by just how ambivalent the song selection was. "You can't resist her," crooned Weezer. "I'll never trust a word you say," retorted Heavens to Betsy. "I wish that I could make her see," moaned American Hi-Fi. The whole thing was a jumble of conflicting emotions, the kind any bad separation churns up. Heard with new ears, Hanna's strangled squeak — "Why won't you talk to me?" — seemed right at home.

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